1. Field of the Invention
The present general inventive concept relates to a transfer device which transfers an image to a printing medium, and an image forming apparatus having the same.
2. Description of the Related Art
In general, image forming apparatuses, such as copiers, printers, facsimile machines, and multi-function machines embodying the functions of the above mentioned devices in a single device, have a function of printing an image on a printing medium. Such image forming apparatuses include a feeding unit to feed the printing medium, a developing unit to develop an image on an photoconductive medium, a transfer device to transfer the developed image onto the printing medium, a fixing unit to fix the transferred image onto the printing medium, and a discharging unit to discharge the printing medium to the outside. Among these units, an example of the transfer device is illustrated in FIG. 1.
Referring to FIG. 1, a transfer device of a conventional image forming apparatus includes a transfer belt 20, which is supported and rotated by a pair of rollers 11 and 12. The transfer belt 20 receives an image from a photoconductive medium and transfers the received image onto a printing medium while rotating. At this time, one of the pair of rollers 11 and 12 is a driving roller 11, which receives a driving force from a driving source, and the other is a tension roller 12. Both ends of the tension roller 12 are supported by an elastic member 12a to apply a tension to the transfer belt 20.
However, the transfer belt 20 meanders in an axial direction of the tension roller 12 while rotating. Such a meandering operation of the transfer belt 20 during rotation causes the transfer quality to deteriorate and damages the transfer belt 20. In order to address such a problem, a method is provided in which a supporting projection 21 is formed on an inside surface of the transfer belt 20, and a guide groove 12b is formed in the tension roller 12 to engage with the supporting projection 21.
However, even if the supporting projection 21 and the guide groove 12b are provided, the transfer belt 20 continuously meanders due to changes in the elastic force of the elastic member 12a which is applied to the transfer belt 20, and deviates from the rotation path of the transfer belt 20. If the transfer belt 20 meanders for an extended period of time, the supporting projection 21 may also become disengaged from the guide groove 12b. 